Experimental data conclusively shows that the weak van der Waals interactions between alkane molecules, < 1.5% the strength of covalent bonding on a per carbon atom basis, modify the carbon Is near edge X-ray absorption fine structure (NEXAFS) spectrum significantly in ordered solids, both in intensity, spectral shape, peak position, and dichroic signature. This constitutes a further breakdown of the 'building block' model, or, more precisely, even a molecular model in interpreting NEXAFS spectra. These observations have significant implications for the interpretation and use of NEXAFS spectra from any crystalline or semi-crystalline macromolecules, small molecules, or other weakly interacting systems. (c) 2006 Elsevier B.V. All rights reserved.